\chapter{Conclusion}
Reviewing the results, it could be stated, that assessing service granularity related to service models has been confirmed appropriate. This finding can be seen as an addition to the knowledge base, considering the DS approach \parencite{Hevner2004}. With respect to the designed artifact, utility and efficacy has been understood, but limited as firstly no appropriate tools are in place, which are a prerequisite of measuring service granularity in a more sophisticated way. Secondly, most of the recommended metrics require field tests to be proved to deliver reliable results.

\noindent
Anyhow, based on the gathered results using metrics in the context of SOA seems to be an exhaustive challenge, as prerequisites are in its infancy, if more sophisticated measurements are considered to be used in the practice. As one alternative with respect to measurements, is to step back and take easier metrics, which do not require any additional information, as these metrics only require interface related information, which could be gathered once the service is technically designed. This has the crucial drawback, that service granularity is not analyzed during the SO modelling phase, thus an interactive approach by means of a tool to optimize the service granularity could hardly be achieved. Worth mentioning thereby is, that trying to optimize the granularity at design-time is having more potential, than having a retrospective during build phase or even in the maintenance phase.

\noindent
Very promising are the approaches around conceptual information, which takes semantic information into consideration, when coupling and cohesion are determined. Furthermore, there will be lots of research coming up in the area of external software attributes, which has not been considered in detail in this thesis.

\noindent
With respect to the practice, there is still much homework left, as difficulties in Business-It alignment become obvious in various areas. Starting at the business process decomposition and advancing to the SO modelling, a tool support capable of providing a coherent view on business process related matters and IT matters with appropriate coarseness of information for the respective stakeholder is required, in case SOA becomes business-critical and large-scaled. Believing the results of the interviews, there is potential seen, which could simplify involved stakeholders' job.

\noindent
As the DS approach intends to outline further calls for actions, to be considered in the next build-and-evaluate loop, the following points are seen relevant in the context of this thesis:
\begin{itemize}
  \item What are the limitations of using metrics, which only use interface related information to measure service granularity and its dependent parameters?
  \item What kind of functionality need to be considered by a tool providing to business and IT a common view on business processes and software services?
  \item Do proposed metric suites achieve highly significant results in field tests?
  \item How can be external structural software attributes related to the designed artifact?
  \item Do metrics correlate (there may be correlation between group of metrics as stated in results of literature review)?
\end{itemize}

\noindent
An interesting point to keep in mind is the direction of the SOA practice in the upcoming years, as it could be stated as a result of this thesis, that the more complex a SOA becomes, the more effort is required to stay on a sustainable track.  